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select * from table where column * 'value';

I accidentally wrote * for my where statement instead of =, and the query returned all rows in the table.

Made me wonder why an error wasn't thrown instead.

What does the * operator do in a where statement?

2

The SQL

WHERE column * value

is a numeric operation of multiplication, and when the value of the expression (column * value) isn't 0, that is equivalent to TRUE so will return the row.

  • 2
    Maybe you should remark this syntax is only valid for MySQL and SQLLite. – McNets Feb 12 at 10:39
  • Starting with V11 this is also valid in Db2 (as long as the multiplication is valid) – Lennart Feb 12 at 11:29
  • In MySQL, if column and/or 'value' are strings, you get a Warning " Truncated incorrect DOUBLE value:..." for each string. – Rick James Feb 12 at 19:40
2
SELECT * FROM <MY_TABLE> WHERE <COL_NAME> * 1;

Although this syntax works for MySQL 8.0 and SQLite 3.8 you will get an error on mostly all other RDBMS.

SQL Server 2017

An expression of non-boolean type specified in a context where a condition is expected, near ';'.

PostgreSQL 11

For integer columns:

ERROR: argument of WHERE must be type boolean, not type integer

For text/varchar columns

ERROR: operator does not exist: character varying * integer

Oracle 18c

ORA-00920: invalid relational operator

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