db--operator

1. Arithmetic operators

• +,
• -,
• *
• /, DIV,
• %, MOD
• In division and modulo operations, if the divisor is 0, it will be an illegal divisor and the return result is null
  
  

2. Comparison operators

• =
• <>! =
• <=>//null security Equals (Null-safe)
• <
• <=
• >
• >=
• Between//x between A and B-a <= x <= b
• Inch
• Is NULL
• is not NULL
• Like
• REGEXP, rlike//string REGEXP String_pat returns 1 when string string contains string_pat-matched strings
• MySQL allows the user to compare the left and right operands of an expression, return 1 if the result is true, return 0 for false, and return NULL if the comparison result is indeterminate
• Comparison operators can be used to compare numbers, strings, and expressions. Numbers are compared as floats, and strings are compared in a case-insensitive manner.
• Null cannot be compared with =.
• <=> and = similar, 1 when the operands are equal, except that the value of a timely operation is null and can be correctly compared.

3. Logical operators

• Not,!

Not NULL return value is NULL

• And, &&

When all operands are non-0 values and are NOT NULL, the computed result is 1, when 1 or more operands are 0 o'clock, the result is 0, any one of the operands is null and the return value is null

• OR, | |

When the two operands are all non-null values, if either operand is a non-0 value, the result is 1, otherwise the result is 0. When there is an operand of NULL, if the other operand is a non-0 value, the result is 1, otherwise null. Two operands are null, the resulting result is null.

• XOR//different or

When either operand is null, the return value is null, and for non-null operands, if the two logical false values are different, the result 1 is returned, otherwise 0

db--operator