SQL Dialects Reference/Functions and expressions/Misc expressions
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[edit] String functions
This page includes comparison tables which can be big and complex.
While it's perfectly all right to view them in their complete state, it is recommended to install a comparison tables extension that would allow to select particular columns of interest for comparison.
| Function | Since SQL | Standard | DB2 | SQLite | MySQL | PostgreSQL | Firebird | Virtuoso | Oracle | MSSQL | Linter |
|---|---|---|---|---|---|---|---|---|---|---|---|
| Convert data from one data type to another | 92 | CAST() | ? | ? | ? | CAST(expression AS type) or :: | CAST(expression AS type) | ? | CAST(), TO_* | CAST(), CONVERT() | CAST(expression as type) CASTexpression as type TO_CHAR TO_NUMBER TO_DATE |
| Return the first non-NULL value from a list of values | 92 | COALESCE(val1, val2, ...) | COALESCE(val1, val2) | ? | COALESCE(val1, val2) | COALESCE(val1, val2) | COALESCE(val1, val2) | ? | COALESCE(val1, val2) | COALESCE(val1, val2, ...), ISNULL(val1, val2) | NVL(val1,val2) COALESCE(val1, val2, ...) |
| Return NULL if two values are equal | 92 | NULLIF(val1, val2) | ? | ? | ? | NULLIF(val1, val2) | ? | ? | NULLIF(val1, val2) | NULLIF(val1, val2) | NULLIF(val1, val2) |
