An expression of non-boolean type specified in a context where a condition is expected, near ‘%.*ls’.

Error Message:
Msg 4145, Level 15, State 1, Line 7
An expression of non-boolean type specified in a context where a condition is expected, near ‘%.*ls’.

Severity level:
15.

Description:
This error message appears when you try to use a non-boolean expression in the context where a boolean expression is expected.

Consequences:
The SQL statement cannot be parsed and further execution is stopped.

Resolution:
Error of the Severity level 15 are generated by the user and are corrigible by the user. The statement cannot be run this way. It must evaluate to a boolean result.

Versions:
All versions of SQL Server.

Example(s):
IF OBJECT_ID(‘dbo.t’) IS NOT NULL
    DROP TABLE dbo.t;
GO

CREATE TABLE dbo.t
(
    c1 int
);
GO

SELECT
    c1
FROM
    dbo.t
WHERE
    1;

Remarks:
In the above example we try to run a query that tries to use the non-boolean expression 1 in the WHERE clause. This raises the error.