SQL function equivalents for warehouse migrations
SQL Server, Oracle and Teradata functions and their Snowflake, Databricks and BigQuery equivalents, with the behavior differences that break migrated queries.
Migration checklists
SQL Server functions
| Function | Purpose | Snowflake | Databricks | BigQuery |
|---|---|---|---|---|
| CHARINDEX | Position of a substring | Same name | Same name | Rewrite |
| CONVERT | Convert type, with date style codes | Rewrite | Rewrite | Rewrite |
| DATEADD | Add an interval to a date | Same name | Same name | Rewrite |
| DATEDIFF | Difference between two dates | Same name | Same name | Rewrite |
| EOMONTH | Last day of the month | Rewrite | Rewrite | Rewrite |
| GETDATE | Current date and time | Same name | Same name | Rewrite |
| IIF | Inline if-then-else | Different name | Different name | Different name |
| ISNULL | Replace NULL with a value | Different name | Different name | Different name |
| LEN | Length of a string | Same name | Same name | Different name |
| STRING_AGG | Concatenate values of a group | Different name | Same name | Same name |
| STUFF | Replace part of a string | Different name | Different name | Rewrite |
| TOP | Limit the number of rows | Same name | Rewrite | Rewrite |
Oracle functions
| Function | Purpose | Snowflake | Databricks | BigQuery |
|---|---|---|---|---|
| ADD_MONTHS | Add months to a date | Same name | Same name | Rewrite |
| DECODE | Map values (switch) | Same name | Same name | Rewrite |
| DUAL | One-row dummy table | Rewrite | Rewrite | Rewrite |
| LISTAGG | Concatenate values of a group | Same name | Same name | Different name |
| NVL | Replace NULL with a value | Same name | Same name | Different name |
| ROWNUM | Row number pseudocolumn | Rewrite | Rewrite | Rewrite |
| SYSDATE | Current date and time | Same name | Rewrite | Rewrite |
| TO_CHAR | Format a date or number as text | Same name | Rewrite | Rewrite |
Teradata functions
| Function | Purpose | Snowflake | Databricks | BigQuery |
|---|---|---|---|---|
| ZEROIFNULL | Replace NULL with zero | Same name | Rewrite | Rewrite |