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23 cze 2013 · I am trying to UPDATE values from a table, but I need to add some conditions. I found the function CASE, but I am not if it is the best method. Here is an example.
UPDATE my_table SET comments = GREATEST(CAST(comments AS signed)-3, 0) WHERE something = 123; or the IF() function: UPDATE my_table SET comments = IF(comments>3, comments-3, 0) WHERE something = 123; or a CASE expression: UPDATE my_table SET comments = CASE WHEN comments>3 THEN comments-3 ELSE 0 END WHERE something = 123;
26 cze 2024 · Updating table rows using subqueries in MySQL enables precise modifications based on specific conditions or values from other tables. This technique leverages subqueries within the SET or WHERE clauses of the UPDATE statement, allowing dynamic and context-specific updates.
UPDATE is a DML statement that modifies rows in a table. An UPDATE statement can start with a WITH clause to define common table expressions accessible within the UPDATE. See Section 15.2.20, “WITH (Common Table Expressions)”. Single-table syntax: UPDATE [LOW_PRIORITY] [IGNORE] table_reference . SET assignment_list . [WHERE where_condition]
In this article, we would like to show you UPDATE query with IF condition in MySQL. Quick solution: UPDATE `table_name` SET `column_name` = IF(condition , if_true, if_false); Practical example. To show UPDATE query with IF condition, we will use the following users table:
17 maj 2024 · Updating a column with a NULL value in MySQL is surprisingly straightforward. Check out this basic syntax: UPDATE table_name. SET column_name= 'N/A' WHERE condition; table_name: The name of your table. column_name: The column you want to turn into NULL. condition: When you want to be selective. If you skip this, it'll update all rows.
An UPDATE statement can start with a WITH clause to define common table expressions accessible within the UPDATE. See Section 13.2.15, “WITH (Common Table Expressions)” . Single-table syntax: UPDATE [LOW_PRIORITY] [IGNORE] table_reference . SET assignment_list . [WHERE where_condition] [ORDER BY ...] [LIMIT row_count] value: {expr | DEFAULT}