TOP-50 MOST IMPORTANT SQL QUERIES: How to Use SQL To Work With Data In A Relational Database Today. (SQL Skills Book 1) by David B. Parnas

Author:David B. Parnas [B. Parnas, David]
Language: eng
Format: azw3
Published: 2020-04-23T00:00:00+00:00

The — single line and the /* .. */ multi-line delimiters empower us to add useful comments to scripts, but this is also used in another valuable way. Sometimes a section of code may not be in use, but we don’t want to delete it, because we anticipate using it again. Here we can simply add the comment delimiter to deactivate it momentarily:

/* This query below is commented so it won't execute*/

/*

SELECT item FROM Orders

WHERE date ALL = (SELECT Order_ID FROM Orders

WHERE quantity > 50)

*/

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