Snowflake union vs union all
Snowflake union vs union all. I've tried only UNION-ing a few of the tables, which sometimes works and sometimes doesn't, depending on the document type. Consider two tables that store colors, one has shades close to red and the other shades close to green. Oct 21, 2010 · UNION performs a DISTINCT on the result set, eliminating any duplicate rows. Thats why, time taken by UNION is more compared to UNION ALL though UNION ALL uses more amount of available resources compared to UNION. Jun 1, 2023 · As far as I understand, in snowflake, the union works as follows- Fails if there are a different number of columns. fruit_name AS fruit_name1, tab1. In the execution order of a query, QUALIFY is therefore evaluated after window functions are computed. SQLにおける UNION/UNION ALL の使い方をデータベース初心者向けにわかりやすく3分で解説します。. DataFrame. But UNION ALL won’t filter any records. you want to rank all farmers in the U. Outer Union Corresponding will display columns that appear only in one dataset, not overlaid by position. So: SELECT column1, column2 FROM table a. Snowflake cannot be run on private cloud infrastructures (on-premises or hosted). Select id, time. Below Aug 3, 2021 · For instance, the filterorg_id=1 or bu_id=1 can be rewritten as two queries with a UNION operator in between. and FRD. fruit_name AS fruit_name2, tab2. price AS price1, tab2. May 17, 2023 · The syntax for a union is: SELECT column_list FROM table1 UNION SELECT column_list FROM table2. Jan 7, 2020 · The UNION set operation combines the results of two or more similar sub-queries into a single result set that contains the rows that are returned by all SELECT statements. ) As Z. please try this approach. T1 and T2 table have many different columns but I need only the ID column from both. union_all. FROM E_OT AS EOT. In practice, we often use the UNION operator to combine data from different tables. Well that's unfortunate. 3. Por ejemplo: En este ejemplo, estamos comparando las columnas «columna1» y «columna2» de «tabla1», «tabla2» y «tabla3». The union is used in the FROM clause of a PIVOT. Nov 9, 2023 · There are two main differences between SQL UNION and UNION ALL: 1. This topic provides reference information about the subquery operators supported in Snowflake. I don't want to update the union_all query manually. SELECT 'D', 3. This method matches the columns in the two DataFrames by their names, not by their positions. Feb 16, 2023 · UNION requires SELECT with table_a as (select '1' as column_name union select '2' union SELECT NULL) select * from table_a; It is also possible to use VALUES : Mar 29, 2022 · Use UNION ALL instead of UNION — These sql constructs are used to combine 2 sets of data. 11. UNION_ALL. Subscribed. until 24hrs ago! I've got a fairly complex CTE in dbt with a UNION ALL at the end that gives the wrong results, it roughly boils down to this query only returns actual_transaction snowflake. col2, MIN(grp) AS source_group. You have your columns in the wrong order: subscriber_status_id in the upper query maps to commitment_start_date in the lower one. dataFrame1. 10. Use Cases: Union and Union All in PySpark . TABLES. e with duplicate elimination). Feb 4, 2014 · 5. union_by_name(other: DataFrame) → DataFrame [source] Returns a new DataFrame that contains all the rows in the current DataFrame and another DataFrame ( other ), excluding any duplicate rows. I've tried commenting out the column in question, which works, but I need that column. UNION ALL. – Robert Monfera. Step 2: Concatenation data (SQL Union All) between Employee_M and Step 1 output. union_all (other: DataFrame) → DataFrame [source] ¶ Returns a new DataFrame that contains all the rows in the current DataFrame and another DataFrame (other), including any duplicate rows. Definition: It aggregates two data sets without removing duplicates if any. unionAllByName() Aug 21, 2023 · SQL Command and output is showed below. crossJoin Two ways to do this: SELECT A FROM L1. If the same row is present in both input DataFrame objects, the returned DataFrame only contains one copy of that row. SELECT *, 2 sortby FROM TABLE_B. ” INSERT operation. UNION/UNION ALL はどちらもSELECT文で抽出した結果を統合する際に利用します。. SELECT A FROM L2. SELECT column_name (s) FROM table2; Note: The column names in the result-set are usually equal to the column names in the first SELECT statement. This is based on real experience. fruit_id AS fruit_id2, tab2. Aug 28, 2020 · Can you not create a view on top of these 12 tables. union (other: DataFrame) → DataFrame [source] ¶ Returns a new DataFrame that contains all the rows in the current DataFrame and another DataFrame (other), excluding any duplicate rows. Here’s how we can rewrite the inner join above: SELECT tab1. crossJoin Jan 10, 2024 · In order to avoid that, the join can be rewritten using UNION operators. If I have a number of fields i would have to add all of them to my GROUP BY. UNION SQL command. UNION ALL SELECT 'Buffered'. Returns a new DataFrame that contains all the rows in the current DataFrame and another DataFrame ( other ), excluding any duplicate rows. Mar 1, 2013 · I have a problem. snowpark. Returns a new DataFrame that contains all the rows in the current DataFrame and another DataFrame ( other ), including any duplicate rows. The T_target table has an ID column of course and an Mar 27, 2024 · Syntax. SELECT 'R', 2. Data types of the column that you are trying to combine should match. Using UNION ALL (SELECT name FROM fruits WHERE type = 'Fresh') UNION ALL (SELECT name FROM fruits WHERE type = 'Dried'); Result: This will display the fruits that are both “Fresh” and “Dried”, but it will keep duplicates. Ich war wahrscheinlich vier Jahre lang Analytiker, bevor ich die SQL-Klausel UNION ALL kannte. UNION. There are three tables: T1, T2, T_target. Third, sort the combined result set by the column specified in the ORDER BY clause. May 7, 2020 · UNION ALL. UNION ALL SELECT 'Not Reported') a. I've tried casting all columns to the same datatype, no luck. Row-by-row insert is costly. UNION output table. . Key. A UNION performs a DISTINCT operation on the results of the query. it gives 'time' is invalid in the select list because it is not contained in aggregate or GROUP BY. Apr 18, 2019 · We can understand it easily with execution plan. A JOIN operation combines rows from two tables (or other table-like sources, such as views or table functions) to create a new combined row that can be used in the query. A UNION ALL does not perform the DISTINCT operation on the results. The UNION ALL is faster than the UNION Reference SQL Command Reference General DML MERGE MERGE¶. expr2 The column or expression to order (rank) by. Hello everyone, I created two tables (Application Data and Booking Data). Both input DataFrames must contain the same number of columns. WHERE RowNum >= 0 AND RowNum <= 10 OPTION(RECOMPILE) Please note that the second part of the UNION ALL now always returns 0 for the RowNum. Based on the comments below, I further elaborated my answer. Stitches together columns based on order alone, not names. Example: The key differences between the sql UNION vs UNION ALL operators are: UNION – Combines like queries and returns only unique records. declare @table1 as table (. Say you have Table Alpha with columns a,b,c, x,y,z and Table Beta with columns a,b,c, h,i,j. You can use this to aggregate distinct values in ARRAYs produced by ARRAY_UNIQUE_AGG. The view will be an union of all these tables. UNION ALL – Combines like queries and will return duplicate records if they exist. DataFrame. For your example you can easily do this by adding a SortOrder to each SELECT. To combine rows from two or more queries into a single result set, we use UNION operator. QUALIFY. Aug 16, 2018 · To fix this you need to: Swap the columns in the second query. UNION ALL does not remove duplicates, and is therefore faster than UNION. Create a Dynamic table as below with self-UNION ALL. It will provide better performance when your table is large. union_all¶ DataFrame. This has the effect of removing duplicates. Oct 3, 2014 · How to do the union of the 2 store procedures: Create a variable as table. Imagine two tables storing customer information: customers and clients. KEY1 = REQ. If you want both descendants and ancestors, make one with for the descendants, another for the ancestors, and then union all those two :) – snowflake. The CTE defines the temporary view’s name, an optional list of column names, and a query expression (i. This topic describes how to use the JOIN construct in the FROM clause. Feb 2, 2024 · UNION ALL operator in SQL is also used to combine the set of one or more select statements as the result. Otherwise by default you should use “union all” in place of “union. Check the refresh mode of the Dynamic table, it reflects FULL as refresh mode. I can hardcode the list of classes into an array, or more preferably, obtain them using a query like so: SELECT DISTINCT(TABLE_SCHEMA) FROM INFORMATION_SCHEMA. Why? Because run_time is one of the columns and it is different in the two queries. ( select * from REQ_1 union select * from REQ_2 union select * from REQ_3 ) as REQ, ( select * from RES_1 union select * from RES_2 union select * from RES_3 ) as RES. Here is how to run a SQL UNION ALL query: SELECT first_name, last_name FROM actor UNION ALL SELECT first_name, last_name FROM customer; Notice how there are two additional records returned from this query (799 vs. Union in Snowflake is a way to merge data from multiple sources or tables without duplicating records. S. status, count(a. Note that this is true even if the second query returns rows, because the values on the rows are different. Oct 26, 2023 · In the vast landscape of SQL, understanding set operations is akin to mastering the art of combining and manipulating data from different sources. Both tables has the same number of columns (32 columns and some of columns are common between the two tables). This data currently sits in two Description. Example: other – the other DataFrame that contains the rows to include. It is like applying DISTINCT on the final result rest. -- ORDER BY . Aug 8, 2023 · ยูเนี่ยน vs ยูเนี่ยนออล. It does not remove duplicate rows between the various SELECT statements (all rows are returned). ARRAY_UNION_AGG. MINUS looks at all the columns. La cláusula EXCEPT muestra las filas que existen en «tabla1», pero no en «tabla2», y la cláusula INTERSECT muestra las filas comunes a «tabla1» y Dec 19, 2016 · If it makes a difference the query needs to run against a DB2 database. As you can see the execution plans are again identical for these two queries, but this time instead of using a MERGE JOIN, a CONCATENATION and SORT operations are used. a SELECT statement). 7K subscribers. unionAll(dataFrame2) Note: In other SQL languages, Union eliminates the duplicates but UnionAll merges two datasets including duplicate records. LEFT OUTER JOIN. Jun 23, 2017 · These records may be found in many different tables, so we need set operators such as union and intersection in SQL to merge them into one table or to find common elements. status) FROM. names. Snowflake is not a packaged software offering that can be installed by a user. For your specific question, given the clarification "The first query should have "priority", so duplicates should be removed from bottom" you can use. Inserts, updates, and deletes values in a table based on values in a second table or a subquery. Mar 28, 2024 · Below are the steps to reproduce the issue: 1. class AS class1, tab1. (SELECT 'Delivered' AS status. OR. This means the records form either query can't be properly combined into a single set. UNION 0. Apr 19, 2023 · Conversely, (Table2 UNION Table3) LEFT JOIN Table1 can be pushed because, in this case, both methods (join after UNION vs. In the following screenshot, we can see the Actual Execution plan. In relational algebra (which SQL isn't) the union result might be one row, though only if the two input relations contained an identical tuple, eg. For example, if you’re ranking farmers to see who produced the most corn (within their state), then you would use the bushels_produced column. Aug 23, 2021 · I am trying to take two tables, Table A and Table B below, and trying to do a union to create a table that stacks them on top of each other as shown in the desired output below. 06. snowflake. The distinct keyword is used to return just one record when a duplicate exists using the distinct() function. The columns in the other DataFrame are rearranged to match the order Jan 24, 2012 · SELECT * FROM Results_CTE a INNER JOIN CalclatedData d ON a. An issue when using UNION ALL function. Snowflake Union ALL: Combines the result set queries without removing duplicates if any; The default set operator for combining query set results is Snowflake Union(i. There is no inherent order, you have to use ORDER BY. but if you want to have all records from Table_A on the top of the result list, then you can add a user defined value, which you can use for ordering: SELECT *, 1 sortby FROM TABLE_A. This query therefore returns the sum of the salaries of the employees in the state of California and the sum of the salaries of the employees in the state of Oregon, yet displays employment_state information (e. Union All Corresponding will not display any columns that appear in only one dataset. This will then keep the records in the order you want: SELECT 'O', 1 SortOrder. KEY1. What does UNION do? What is the difference between UNION and intersect 演算子は、 union [all] および minus （ except ）よりも優先順位が高くなります。 優先順位が等しい演算子は、左から右に処理されます。 括弧を使用して、式を強制的に異なる順序で評価することができます。 Nov 1, 2023 · However, within the table in Understanding dynamic table refresh: Types of queries that support incremental refreshes it says: Dynamic tables support UNION ALL. To achieve a "Sql Union All with “distinct”" then simply replace UNION ALL with UNION. Typically, a SELECT statement’s clauses are snowflake. bulk_sms_numbers. SELECT a. Jul 29, 2012 · A basic UNION will fail because UNION without the ALL has to have the same number of columns from both tables. May 26, 2023 at 6:54 AM. Summary: SQL Union When state is used in the GROUP BY, Snowflake interprets it as a reference to the column name, not the alias. Aug 24, 2022 · I have the same problem as @EmperorEto: the same MS SQL query with the same number of unique rows in each, the only difference is UNION vs UNION ALL. Select StudentID, ExamDate, 2 AS ExamType, '232-442' AS Account, Amounts AS Debit, CAST(NULL AS DECIMAL(18,2)) AS Credit. UNION ----> Less amount of resources used. Make the union of the variables. 4K views 1 year ago Demystifying Data Engineering with Cloud Computing. Mar 18, 2013 · SELECT * FROM TABLE_A. UNION ALL SELECT 'Not Delivered'. They do exactly the same thing except in UNION, an extra step is performed to eliminate duplicate data. You can think of the CTE as a temporary view for use in the statement that defines the CTE. The data types must be compatible. UNION vs UNION ALL Examples. This can be useful if the second table is a change log that contains new rows (to be inserted), modified rows (to be updated), and/or marked rows (to be deleted) in the target table. fruit_id AS fruit_id1, tab1. g. Here is another great article on SQL Set Operations to help reinforce and expand on what you’ve just learned. returns 3 columns with nulls in column 3. . Here is a more comprehensive (sanitised) version of what I need to do. Union All. unionAll() DataFrame. I used SQL server before this and im confused that Snowflake can't use UNION statements? Has anyone with lots of Snowflake experience have a solution to this problem? SELECT. Below conditions to be met to use UNION or UNION ALL commands: 1. class AS class2, tab2. A subquery is a query within another query. union¶ DataFrame. price AS price2 FROM tab1 The DataFrame. The Hive UNION set operation is different from JOIN, which combine the columns from two tables. answered Apr 17, 2014 at 17:39. May 26, 2021 · Given 2 tables SF1 & SF1_V2: Iterate the Information Schema and retrieve the columns for both the tables. This is a known limitation, SELF UNION ALL is not supported for INCREMENTAL refresh mode. But, in PySpark both behave the same and recommend using DataFrame duplicate () function to remove duplicate rows. PARSE_JSON(extra[0]['party'])[0]['trait1'] AS Trait1, COUNT(Trait1) AS T1. Union(): Use this when you want to merge datasets and ensure unique records. create_or_replace_temp_view. We do this using a SQL set operator. Essentially, star schemas offer users a more efficient way to organize data and information in a data warehouse. Snowflake Union & Union All () functions. In diesem Artikel werden wir uns mit den SQL-Klauseln UNION und UNION ALL beschäftigen. UNION takes more work on the server as it has to deduce the duplicates prior to The UNION ALL command combines the result set of two or more SELECT statements (allows duplicate values). The difference between UNION and UNION ALL is that in the UNION ALL operator there are duplicates in the result sets of SELECT statements whereas in the UNION operator, there are no duplicate values. The difference lies within the results; UNION ALL allows duplicate records in the results as UNION does not. UNION will remove duplicates, while UNION ALL will not. Use UNION only if you want to filter the duplicates in the result set. Both tables or queries must have the same number and order of columns in their column_list, and the corresponding columns’ data types must be compatible or convertible. See full list on learnsql. mcclell99 asked a question. It combines the result set from multiple tables and returns distinct records into a single result set. UNION ALL runs faster because of this. If you need to perform a UNION ALL instead, call one of the following methods: DataFrame. SELECT (SUM(addition)) AS [COUNT], MAX([date]) AS [max_date] FROM (SELECT addition, CONVERT(VARCHAR(12),CREATED,102)) as [date] FROM [TABLE_ONE] WHERE CONVERT(VARCHAR(12),CREATED,102) BETWEEN CONVERT(date,@startdate) AND CONVERT(date,@enddate) AND [ServiceID]=@serid UNION ALL SELECT addition, (CONVERT(VARCHAR(12),CREATED,102)) as Apr 6, 2021 · Note that union all is much preferred over union because it does not incur overhead to remove duplicates. UNION ALL always performs better than UNION. Semi-structured and structured data functions. In my attempt below, it ended up assigning nulls to everything in the 'Category' column whereas not all cases of the 'categeory' column should be null. First, execute each SELECT statement individually. Returns an ARRAY that contains the union of the distinct values from the input ARRAYs in a Feb 28, 2023 · UNION und UNION ALL in SQL: Was sie tun und wie sie sich unterscheiden. create_or_replace_view. Oct 24, 2019 · The UNION ALL works perfectly if I comment that column out. SQL Union All Example. ข้อแตกต่างระหว่าง union และ union all คือ union จะเก็บเฉพาะเรคคอร์ดที่ไม่ซ้ำ และลบเรคคอร์ดที่ซ้ำกันออกในขณะที่ทำการเชื่อมข้อมูล Dec 2, 2015 · You're selecting all the combinations of rows over and over again - it's an infinite loop, basically (just with recursion). I assume those are just part of transcribing the question for public consumption. Each SELECT statement within the UNION ALL must have the same number of fields in the result sets with similar data types. QUALIFY does with window functions what HAVING does with aggregate functions and GROUP BY clauses. regardless of which state they live in), then omit the PARTITION BY clause. (. 1. The following comparison table explains their main differences in a quick manner: UNION. Explicitly cast the NULL value to the appropriate type (eg DECIMAL(18,2)) The resulting query will be. It turns out there is, actually, a difference: how columns which only exist in one dataset are handled. In a SELECT statement, the QUALIFY clause filters the results of window functions. See also Bitwise Expression Functions. WHERE TABLE_TYPE = 'BASE TABLE'. For a conceptual explanation of joins, see Working with Joins. 078sec ---> More time taken to execute. Behind-the-scenes Snowflake determines whether the UNION ALL results in "conflicting ROW_ID s, if so, only full refresh is supported. Create a table and insert some data. crossJoin Oct 22, 2009 · Thus, your statement should be: Select id, time. Partitioning it will improve performance. The SQL UNION ALL operator is used to combine the result sets of 2 or more SELECT statements. The result of the query expression is May 5, 2015 · From T-SQL UNION page: The following are basic rules for combining the result sets of two queries by using UNION: The number and the order of the columns must be the same in all queries. “Active”) rather Jul 16, 2020 · In short, the difference between UNION operator and UNION ALL (UNION vs UNION ALL) operator is UNION gives unique results set in the output even though the combined result set has some duplicate records. The UNION operator selects only distinct values by default. UNION after join) will return the same unmatched rows. 2. Using full outer joins, create a column clause (ex: “NULL AS C_EMAIL_ADDRESS”) if the Union all ; Select * from query2 where currency_name not in (select distinct currency_name from query1) Union all ; Select * from query3 where currency_name not in (select distinct currency_name from query2) and currency_name not in (select distinct currency_name from query1) I hope this helps 60. I want to combine the tables like so: SELECT *, 'class1' as class FROM class1. Following is the basic syntax of UNION operator: How to customize formatting for each rich text Headings, paragraphs, blockquotes, figures, images, and figure captions can all be styled after a class is added to the rich text element using the "When inside of" nested selector system. 23. c. May 10, 2016 · Yes, that's the main difference. union() and DataFrame. column1 nvarchar(20) , This is the default unless you use the SQL UNION ALL command. Step 1: Concatenation data (SQL Union) between Employee_F and Employee_All table. The following SQL statement returns the cities (duplicate values also) from both the "Customers" and the "Suppliers" table: Try moving the WHERE condition into the ON clause and using an OUTER join. Snowflake supports most of the standard operators defined in SQL:1999. The UNION version takes 6-8 seconds to execute. Define all the columns that will return the store procedure in the variables of the table. In this blog post, we will explore four essential… Feb 6, 2024 · The dataframe1 and dataframe2 are merged using the union() function. the docs are misleading and should really say Jan 5, 2023 · Both UNION and UNION ALL are clauses used to combine multiple queries into one result set. In comparison, snowflake schemas, which are a variation of star schemas, provide users with more efficiency when snowflake. A CTE (common table expression) is a named subquery defined in a WITH clause. e. ALL / ANY¶ The ALL and ANY keywords can be used to apply a comparison operator to the values produced by a subquery (which can return more than one row). When I combine the two tables using the function "UNION ALL" the output will be only the columns of the first table while Snowflake Union All () function. They overlap on the values ‘yellow’ and ‘tan’. Sí, puedes utilizar ambas cláusulas en la misma consulta. See also: ARRAY_UNIQUE_AGG , Using Arrays to Compute Distinct Values for Hierarchical Aggregations. UNION ALL Examples With Sort on Non-indexed Column Here is another example doing the same thing, but this time doing a SORT on a non indexed column. UNION ALL is also a ‘set operator’ in SQL Server. 797). If Dec 5, 2007 · UNION vs. SELECT * FROM TABLE_B. Apr 14, 2010 · UNION ALL avoids intermediate steps but: 1) it can lead to bloated, hard to maintain code 2) it can lead to unmanageable query plans - if they get too big then the plan viewing tools in sql server can't actually view them 3) if parts of a complex union are similar, or may be used elsewhere in your system consider using table valued functions or A union of two 1-row tables (two multiset relations each with one tuple) would have two rows (tuples) in the resulting relation. and: SELECT column1, column2 FROM table a. UNION ALL not returning as expected. To allow duplicate values, use UNION ALL: SELECT column_name (s) FROM table1. SomeIntKey2 = d. tablea. --First variable. As an example, let’s say that we need a list of all names of customers and employees. SELECT column1, column2, column3 FROM table b. The UNION ALL operator performs -in a similar way to the UNION operator, in the sense that it too combines the result sets of two or more SELECT statements. Because UNION needs to sort the dataset to remove duplicates, it is slower than UNION ALL. Therefore, if performance is a concern and duplicates are not an issue, UNION ALL is a better choice. Second, combine result sets and remove duplicate rows to create the combined result set. Snowflake manages all aspects of software installation and updates. tableb. unionByName() methods perform a UNION. Jan 7, 2015 · You could apply the group by and order by after the union all:. If you want to have the RowNum column for the result of the UNION ALL you need another sub query: Make sure your columns are in the same order for both parts of the union and that they are all of the same type. Each column of both datasets needs to have the same data Oct 6, 2022 · 2022. There are also errors such as flag 1 and table 1 . Syntax¶ Query Operators. It combines the result set from multiple tables and returns all records into a single result set. Jun 4, 2019 · For Oracle DB will be happier if you give it query with UNION ALL compared to UNION. From TableA. self-union of a one-tuple relation. First, let’s create two DataFrame with the same schema. For the last decade I would have said I knew how UNION ALL worked . The UNION ALL version takes 30-90 seconds to execute. SELECT A FROM L3. From dbo. The JOIN subclause specifies (explicitly If you want only a single group (e. May 18, 2021 · Answer: A: If the query was changed to use UNION ALL, a customer might be returned more than once. Requirements to use them properly: The two datasets need to have the same schema or structure (same name of columns in the same order). Returns an ARRAY that contains the union of the distinct values from the input ARRAYs in a column. com Jan 6, 2022 · Snowflake Union: Combines the result set queries and removes duplicates if any. B: A UNION invariably involves more work and is slower as it needs to perform a DISTINCT operation on the results. Erfahren Sie, was sie bewirken und wann sie zu verwenden sind. このページでは初めてSQLを利用する方でも理解できるように すべて図解付き UNION ALL Result. Nov 6, 2019 · select col1 ,col2 from EXT_ABVD union all select col1 ,col2 from EXT_ADAD union all select col1 ,col2 from EXT_AVSA; I would like to do this on a regular basis (daily for example), and every time this runs there may be new tables starting with 'EXT_'. These operators include arithmetic operators (such as + and - ), set operators (such as UNION ), subquery operators (such as ANY ), etc. Snowflake uses virtual compute instances for its compute needs and a storage service for persistent storage of data. Columns count should be same in both tables. UNION removes duplicate rows from the combined dataset, while UNION ALL does not. Union in Snowflake & Union ALL Syntax; SELECT UNION SELECT Feb 13, 2022 · Knowledge Amplifier. – Vijchti. union_by_name. WITH CTE_L AS. SELECT *, 'class2' as class FROM class2. Returns an input array converted to a string by casting all values to strings (using TO_VARCHAR) and concatenating them (using the string from the second argument to separate the elements). During such operations, we take two or more results from SELECT statements and create a new table with the collected data. Jul 6, 2021 · Trying to combine results which are the following results on snowflake. You can think of it like this: union will stack the records from both tables one on top of the others, while cross join will stack them side by side, while pairing each row from the first table to each row of the second table. Example:: Dec 22, 2020 · Will always return all unique rows from Table_A. Feb 13, 2020 · Snowflake does not support "DISTINCT ON", but you can use QUALIFY and ROW_NUMBER to produce the same result: SELECT * from ( select * from values (123,11,12,'a' ) as tableA (allowed_id, col2, col3, table_name) union all select * from values (123,21,22,'b' ) as tableA (allowed_id, col2, col3, table_name) union all select * from values (123,31,32,'c' ) as tableA (allowed_id, col2, col3, table Sep 5, 2023 · Snowflake schemas are good for data warehouses whereas star schemas are better for datamarts with simple relationships. zd sk td zi na wb jg cn lc un