Basic syntax of the SQL UNION Let's look at how UNION functions in SQL. The syntax for it is as follows: SELECT column_1, column_2, ... column_n FROM table_1 UNION SELECT column_1, column_2, ... column_n FROM table_2 ... UNION SELECT column_1, column_2, ... column_n FR...
syntaxsql 複製 { <query_specification> | ( <query_expression> ) } { UNION [ ALL ] { <query_specification> | ( <query_expression> ) } [ ...n ] } 引數 <query_specification> | ( <query_expression> ) 是查詢規格或查詢運算式,會傳回要與另一個查詢規格或查詢運算式之資料合併的資料。
syntaxsql 複製 { <query_specification> | ( <query_expression> ) } { UNION [ ALL ] { <query_specification> | ( <query_expression> ) } [ ...n ] } 引數 <query_specification> | ( <query_expression> ) 是查詢規格或查詢運算式,會傳回要與另一個查詢規格或查詢運算式之資料合併的資料。
syntaxsql {<query_specification>| (<query_expression>) } {UNION[ALL] {<query_specification>| (<query_expression>) } [ ...n ] } 参数 <query_specification> | ( <query_expression> ) 是一个查询规范或查询表达式,用以返回要与另一个查询规范或查询表达式所返回的数据合并的数据。 属于 UNION 运算...
源自MySQL 5.7 官方手册:13.2.9.3 UNION Syntax 一、UNION语法 UNION用于将多个SELECT语句的结果合并到一个结果集中。 SELECT...UNION[ALL | DISTINCT]SELECT...[UNION [ALL | DISTINCT]SELECT...] 将会使用第一个SELECT语句中的列名称作为返回结果的列名称。而且在每个SELECT语句的相应位置中列出的选定列应具有相...
Syntax # UNION syntax. SELECTcolumn-names1 FROMtable-name1 UNION SELECTcolumn-names2 FROMtable-name2 UNION ALL syntax. SELECTcolumn-names1 FROMtable-name1 UNIONALL SELECTcolumn-names2 FROMtable-name2 More Examples # SQL UNION Problem:List all unique countries for customers and suppliers. ...
The purpose of the SQLUNIONandUNIONALLcommands are to combine the results of two or more queries into a single result set consisting of all the rows belonging to all the queries in the union. The question becomes whether or not to use theALLsyntax. ...
SQL Union vs Join - Learn the differences between SQL Union and Join, their usage, and how they can be applied in database queries to combine data from multiple tables effectively.
SQL Union Syntax SELECT column1, column2, ... FROM table1 UNION SELECT column1, column2, ... FROM table2; Here, column1,column2, ... are the column names required for the union table1 and table2 are the names of the tables to fetch the columns from UNION combines the columns in...
UNION ALL Syntax TheUNIONoperator selects only distinct values by default. To allow duplicate values, useUNION ALL: SELECTcolumn_name(s)FROMtable1 UNIONALL SELECTcolumn_name(s)FROMtable2; Note:The column names in the result-set are usually equal to the column names in the firstSELECTstatement...