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18 mar 2014 · In MySQL, can I select columns only where something exists? For example, I have the following query: select phone, phone2 from jewishyellow.users where phone like '813%' and phone2
29 lis 2019 · If you simply want to check if a column is null or empty, you may be better off doing this: SELECT myCol FROM MyTable WHERE MyCol IS NULL OR MyCol = '' See TRIM COALESCE and IS NULL for more info.
6 cze 2024 · We can use the function NULLIF to compare and check if the column contains null or empty values: SELECT id, name FROM Department WHERE NULLIF(TRIM(code), '') IS NULL; The NULLIF function evaluates its two arguments, returning NULL if they are equal.
27 gru 2014 · How to set WHERE to select another column if the column is NULL? SELECT * FROM TABLE WHERE date_active = 'value'. If date_active is NULL it should use the date_created column.
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.
5.3.4.3 Selecting Particular Columns. If you do not want to see entire rows from your table, just name the columns in which you are interested, separated by commas. For example, if you want to know when your animals were born, select the name and birth columns: mysql> SELECT name, birth FROM pet; +----------+------------+ | name | birth | ...
2 lut 2024 · The steps to filter out the null or empty column values present inside the table are given in the section ahead. The syntax for NULL or Empty check is: Select expression [, expression2] ... FROM table-name. [WHERE column-name IS NULL or column-name = '']
