What does =* mean?

This:

WHERE t.column =* s.column

...is old TSQL (pre SQL Server 2005) outer join syntax, and is not an ANSI JOIN.

sql sql-server database tsql

I believe that is old syntax indicating an outer join condition from table1 to table2

Old style:

SELECT * FROM table1, table2WHERE table1.yr =* table2.yr -1

New style (SQL92):

SELECT * FROM table2 LEFT OUTER JOIN table1 ON table1.yr = table2.yr - 1

sql sql-server database tsql

This is the old style syntax for expressing joins

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