Why Does My MySQL UPDATE Query Across Multiple Tables Result in an 'Unknown column' Error?

MySQL 'Unknown column in 'field list'' Error When Updating Multiple Tables

Encountering MySQL error #1054 while attempting an update query? Here's why:

The provided query attempts to update two tables, MASTER_USER_PROFILE and TRAN_USER_BRANCH, using the syntax:

UPDATE MASTER_USER_PROFILE, TRAN_USER_BRANCH
SET MASTER_USER_PROFILE.fellow='y'
WHERE MASTER_USER_PROFILE.USER_ID = TRAN_USER_BRANCH.USER_ID
AND TRAN_USER_BRANCH.BRANCH_ID = 17

However, when performing an update across multiple tables, it is important to use the correct syntax. In this case, the error "Unknown column 'y' in 'field list'" arises because MySQL interprets the value 'y' as a column name due to the single quotes surrounding it.

Resolving the Error

To resolve this issue, the value 'y' should be enclosed in double quotes or enclosed with backticks (`) as shown in the below code:

UPDATE MASTER_USER_PROFILE, TRAN_USER_BRANCH
SET MASTER_USER_PROFILE.fellow="y"
WHERE MASTER_USER_PROFILE.USER_ID = TRAN_USER_BRANCH.USER_ID
AND TRAN_USER_BRANCH.BRANCH_ID = 17;

By applying this correction, MySQL will correctly interpret 'y' as a value to update the fellow column of MASTER_USER_PROFILE.

Quoting Conventions

To avoid such errors in the future, it is crucial to adhere to proper quoting conventions. Single or double quotes should be used for values, strings, and similar, while backticks should be reserved for column names.

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