Search results
Turn the EXISTS clause into a subquery instead within an IF function. SELECT IF( EXISTS( SELECT * FROM gdata_calendars WHERE `group` = ? AND id = ?), 1, 0) In fact, booleans are returned as 1 or 0. SELECT EXISTS( SELECT * FROM gdata_calendars WHERE `group` = ? AND id = ?)
Here is an example that uses date functions. The following query selects all rows with a date_col value from within the last 30 days: -> WHERE DATE_SUB(CURDATE(),INTERVAL 30 DAY) <= date_col; The query also selects rows with dates that lie in the future. Functions that expect date values usually accept datetime values and ignore the time part.
26 sty 2024 · Assessing whether a row exists in a MySQL table is a fundamental operation that can be performed in several ways. Using the EXISTS clause is usually the best option due to its performance. However, for small datasets or specific use-cases other methods like COUNT() or LIMIT can be suitable.
18 sie 2017 · I have a procedure that should check if a record exists or not for particular date range, if exists then fetch the record else fetch last 20 record. For this i have to write a query multiple times...
The EXISTS operator is used to test for the existence of any record in a subquery. The EXISTS operator returns TRUE if the subquery returns one or more records. Below is a selection from the "Products" table in the Northwind sample database: And a selection from the "Suppliers" table:
The EXISTS operator is often used to test for the existence of rows returned by the subquery. The following illustrates the basic syntax of the EXISTS operator: SELECT select_list FROM a_table WHERE [NOT] EXISTS (subquery); Code language: SQL (Structured Query Language) (sql)
Most simplest way is to use a IF ().
