The rules of and, or and as in mysql

The rules of AND, OR and AS in MySQL: AND: true when all conditions are true, and the priority is higher than OR; OR: true when one condition is true, and the priority is lower than AND; AS: for selection The column designation alias is followed by the column alias.

Rules for AND, OR and AS in MySQL

AND

• Combining two or more conditions together, the entire expression is true only when all conditions are true.
• The AND operator has higher precedence than the OR operator.
• Grammar: condition1 AND condition2

OR

• Combine two or more conditions Together, as long as one of the conditions is true, the entire expression is true.
• The OR operator has lower precedence than the AND operator.
• Syntax: condition1 OR condition2

AS

• Specifies the columns selected from the query Alias.
• AS keyword followed by column alias.
• Syntax: SELECT column_name AS column_alias

Rules

• AND and OR operators can be combined use.
• AS aliases can be used with the AND and OR operators.
• Brackets can be used to control the precedence of operators.

• For example:

  <code>SELECT * FROM table_name
  WHERE (column1 = value1 OR column2 = value2)
  AND column3 = value3
  AS result_alias;</code>

  In this query:

• ##OR The operator combines column1 and The conditions of column2 are combined together. The
• AND operator combines the conditions of the OR operator with the conditions of column3. The
• AS keyword specifies an alias for the query result as result_alias.

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