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1 lis 2018 · The two* (or more) values in parentheses is called a row-constructor. Other ways that express the same idea: -- works in PostgreSQL, DB2 SELECT whatever FROM t WHERE (col1, col2) IN ( VALUES (val1a, val2a), (val1b, val2b), ...)
SELECT * FROM my_table WHERE (x0, y0, x1, y1) IN ((4, 3, 5, 6), ... ,(9, 3, 2, 1)); I would expect MySQL to use the composite index that you have described. But, if it doesn't you could do: SELECT * FROM my_table WHERE x0 = 4 AND y0 = 3 AND x1 = 5 AND y1 = 6 UNION ALL . . . SELECT * FROM my_table WHERE x0 = 9 AND y0 = 3 AND x1 = 2 AND y1 = 1
26 sty 2024 · By understanding how to combine the WHERE, GROUP BY, and HAVING clauses in MySQL, you can create powerful, precise queries that return exactly the data you need. Remember to utilize them in the correct order and beware of the common pitfalls associated with their use.
The MySQL WHERE Clause. The WHERE clause is used to filter records. It is used to extract only those records that fulfill a specified condition. WHERE Syntax. SELECT column1, column2, ... FROM table_name. WHERE condition; Note: The WHERE clause is not only used in . SELECT statements, it is also used in UPDATE, DELETE, etc.! Demo Database.
Summary: in this tutorial, you will learn how to use the MySQL WHERE clause in the SELECT statement to filter rows from the result set. Introduction to MySQL WHERE clause. The WHERE clause allows you to specify a search condition for the rows returned by a query. The following shows the syntax of the WHERE clause:
IN Syntax. SELECT column_name (s) FROM table_name. WHERE column_name IN (value1, value2, ...); or: SELECT column_name (s) FROM table_name. WHERE column_name IN (SELECT STATEMENT);
You can use a WHERE clause to combine row selection with column selection. For example, to get birth dates for dogs and cats only, use this query:
