Search results
21 sie 2010 · I'm having a problem where when I try to select the rows that have a NULL for a certain column, it returns an empty set. However, when I look at the table in phpMyAdmin, it says null for most of the rows. My query looks something like this: SELECT pid FROM planets WHERE userid = NULL Empty set every time.
18 mar 2014 · We can use CASE for setting blank value to some char or String. I am using NA as Default string. SELECT phone, CASE WHEN phone2 = '' THEN 'NA' END AS phone2 ELSE ISNULL(phone2,0) FROM jewishyellow.users WHERE phone LIKE '813%'
IS NOT NULL Comparison Operator. By far the simplest and most straightforward method for ensuring a particular column’s result set doesn’t contain NULL values is to use the IS NOT NULL comparison operator. For example, if we want to select all records in our books table where the primary_author column is not NULL, the query might look like this:
I tried the following: SELECT column_name. FROM information_schema.columns. WHERE table_name = "table_name". AND EXISTS (. SELECT DISTINCT column_name FROM table_name WHERE column_name IS NOT NULL. ) But this also returns the column names where all the entries are NULL.
21 cze 2024 · The WHERE clause is used to specify a condition while fetching data from a single table or by joining multiple tables. Only the records that meet the specified condition are retrieved. Syntax: SELECT column1, column2, ... FROM table_name.
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.
This tutorial shows you how to use MySQL WHERE clause to filter rows based on specified conditions.
