Want to table A and B combined query out the effect of C table, query, please how to write, if the data amount is larger, have relatively high query efficiency? (column B A return value of the last in A column) don't know if I express myself clear, please

CodePudding user response:

The top once, for help,

CodePudding user response:

Refer to the https://www.cnblogs.com/gmq-sh/p/6848929.html

CodePudding user response:

refer to the second floor dybinchn response:

refer to the https://www.cnblogs.com/gmq-sh/p/6848929.html

Thank you, but A table column will contain the B table B column multiple values (such as A column of the first line) how to query?

CodePudding user response:

A table split first, and then matching,
To use regular, matches the first letter from bottom
The union joint query can