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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.
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:
For example, if the table contains 1 and 2 in the id column and 1 is updated to 2 before 2 is updated to 3, an error occurs. To avoid this problem, add an ORDER BY clause to cause the rows with larger id values to be updated before those with smaller values: UPDATE t SET id = id + 1 ORDER BY id DESC;
16 kwi 2016 · However, given how the conditions are re-used in your UPDATE statement, you could also take a different approach altogether: represent the affected IDs and the new values as a derived table and use an update with a join:
The MySQL UPDATE Statement. The UPDATE statement is used to modify the existing records in a table. UPDATE Syntax. UPDATE table_name. SET column1 = value1, column2 = value2, ... WHERE condition; Note: Be careful when updating records in a table! Notice the . WHERE clause in the UPDATE statement.
Use IF...THEN...ELSE statement to execute a block of statements if a specified condition is true and an alternative block of statements if the condition is false. Use IF...THEN...ELSEIF...ELSE statement to evaluate multiple conditions sequentially and execute corresponding blocks of statements based on the first true condition, with an optional ...
During test case development, it is useful to process all input even if errors occur so that you can see all errors at once, such as those that occur due to typographical or syntax errors. Otherwise, you can see and fix only one scripting problem at a time.
