Answers for "mysql update select"

mysql update from select

UPDATE t1
SET t1.COL1 = t2.COL1, t1.COL2 = t2.COL2
FROM MY_TABLE AS t1
INNER JOIN MY_OTHER_TABLE AS t2 ON t1.COLID = t2.ID
WHERE t1.COL3 = 'OK';

mysql update add to existing value

mysql> UPDATE tableName SET sometotal = sometotal+10 WHERE Id = 4;

update select mysql

UPDATE tableA a
INNER JOIN tableB b ON a.name_a = b.name_b
SET validation_check = if(start_dts > end_dts, 'VALID', '')
-- where clause can go here

MySQL UPDATE

The UPDATE statement updates data in a table. It allows you to change the values in one or more columns of a single row or multiple rows.

The following illustrates the basic syntax of the UPDATE statement:

UPDATE [LOW_PRIORITY] [IGNORE] table_name 
SET 
    column_name1 = expr1,
    column_name2 = expr2,
    ...
[WHERE
    condition];
In this syntax:

First, specify the name of the table that you want to update data after the UPDATE keyword.
Second, specify which column you want to update and the new value in the SET clause. To update values in multiple columns, you use a list of comma-separated assignments by supplying a value in each column’s assignment in the form of a literal value, an expression, or a subquery.
Third, specify which rows to be updated using a condition in the WHERE clause. The WHERE clause is optional. If you omit it, the UPDATE statement will modify all rows in the table.